<html>
    <style>
    .i-box {
    width: 100%;
    margin: 10px auto;
}
.layout-l {
    color: white;
    line-height: 30px;
}
.layout-l > .i-left {
    float: left;
    width: 300px;
    background-color: #0000ff;
}
.layout-l > .i-right {
    overflow: auto;
    background-color: #ff0000;
}
.layout-r {
    color: white;
    line-height: 30px;
}
.layout-r > .i-right {
    float: right;
    width: 300px;
    background-color: #0000ff;
}
.layout-r > .i-left {
    overflow: auto;
    background-color: #ff0000;
}
.layout-both {
    color: white;
    line-height: 30px;
}
.layout-both > .i-left {
    float: left;
    width: 500px;
    background-color: #0000ff;
}
.layout-both > .i-right {
    float: right;
    width: 700px;
    background-color: #ff0000;
}
.layout-three {
    color: white;
    line-height: 30px;
}
.layout-three .i-left {
    float: left;
    width: 300px;
    background-color: #0000ff;
}
.layout-three .i-mid {
    margin-left: 310px;
    margin-right: 310px;
    background-color: #ff0000;
    overflow: auto;
}
.layout-three .i-right {
    float: right;
    width: 300px;
    background-color: #008000;
}
.layout-three-ll {
    color: white;
    line-height: 30px;
}
.layout-three-ll .i-left {
    float: left;
    width: 200px;
    background-color: #0000ff;
}
.layout-three-ll .i-mid {
    float: left;
    width: 200px;
    background-color: #ff0000;
}
.layout-three-ll .i-right {
    margin-left: 400px;
    background-color: #008000;
}
.layout-three-rr {
    color: white;
    line-height: 30px;
}
.layout-three-rr .i-left {
    margin-right: 400px;
    background-color: #008000;
}
.layout-three-rr .i-mid {
    float: right;
    width: 200px;
    background-color: #ff0000;
}
.layout-three-rr .i-right {
    float: right;
    width: 200px;
    background-color: #0000ff;
}
    </style>
<body>
<div class="i-box clearfix">
    <div class="layout-l clearfix">
        <div class="i-left">
            <p>左侧定宽</p>
        </div>
        <div class="i-right">
            <p>右侧自适应</p>
        </div>
    </div>
</div>

<div class="i-box clearfix">
    <div class="layout-r clearfix">
        <div class="i-right">
            <p>右侧定宽</p>
        </div>
        <div class="i-left">
            <p>左侧自适应</p>
        </div>
    </div>
</div>

<div class="i-box clearfix">
    <div class="layout-both clearfix">
        <div class="i-left">
            <p>左侧定宽</p>
        </div>
        <div class="i-right">
            <p>右侧定宽</p>
        </div>
    </div>
</div>

<div class="i-box clearfix">
    <div class="layout-three clearfix">
        <div class="i-left">
            <p>左侧定宽</p>
        </div>
        <div class="i-right">
            <p>右侧定宽</p>
        </div>
        <div class="i-mid">
            <p>中间自适应</p>
        </div>
    </div>
</div>

<div class="i-box clearfix">
    <div class="layout-three-ll">
        <div class="i-left">
            <p>左侧定宽</p>
        </div>
        <div class="i-mid">
            <p>左侧定宽</p>
        </div>
        <div class="i-right">
            <p>右侧自适应</p>
        </div>
    </div>
</div>

<div class="i-box clearfix">
    <div class="layout-three-rr">
        <div class="i-mid">
            <p>右侧定宽</p>
        </div>
        <div class="i-right">
            <p>右侧定宽</p>
        </div>
        <div class="i-left">
            <p>左侧自适应</p>
        </div>
    </div>
</div>
</body>
</html>